1. Field of the Invention
The present invention is directed to an improved torque measuring device, and particularly to a torque measuring device which is very well adapted for testing vehicles in association with chassis dynamometers and the like.
2. Brief Description of the Prior Art
A conventional method and device for measuring the torque output of a rotating shaft involves the use of an "in-line" torque meter assembly which has a member rotating together with the shaft. The member suffers a torsional deformation which is proportional to the torque output of the shaft. A suitable transducer is operatively coupled to the rotating member and sends off electric or radio signals proportional to the torsional deformation of the member.
In dynamometers of the type used in testing automotive engines, and particularly vehicles, torque is usually measured in the following manner. A stator of the dynamometer is supported upon ball bearings or oil floated trunnion bearings for rotation in coaxial relationship with a dynamometer rotor which is driven by the drive wheels of the vehicle. The reaction torque of the stator is then measured by strain gauges, load cells or like devices. The torque meters of this type are usually termed in the prior art, reaction torque type torque meters.
The above summarized prior art devices suffer from many disadvantages. For example, rotating in-line type torque meter assemblies require a radio transmitter or suitable slip rings and brushes to transmit the radio or electric signals which are proportional to the torsional deformation of the rotating member. In the reaction-torque type torque meters mounting of the stators requires large, expensive heavy-duty ball bearings which introduce frictional forces unfavorably influencing the torque measurements. Oil floated trunnion mounting of the stator of reaction torque type torque meters, on the other hand, is rather expensive.
Accordingly, the present invention is directed to a torque meter which overcomes many of the disadvantages of the prior art, is relatively economical to manufacture, and in certain embodiments is capable of directly measuring the torque output of a rotating shaft without the use of an in-line rotating member.